Was waiting to board a flight to DEN from PHL this morning, and a gate agent (not the ones working the flight) was making very frequent announcements (at least every couple of minutes) encouraging people on the Denver flight to check their carry on luggage for free to their final destination.
While I may have heard similar announcements before, never in such an aggressive manner as this agent. He told people to look at their boarding pass, and if they had a zone 4, there might not be overhead space left then they should see him to check their bags (plane was a 757).

I guess being proactive was a good thing and it certainly will discourage people from paying the checked baggage fee.

He had about 3 or 4 takers.